I thought locking was red, unlocking was green.

The diagrams I've seen show red going from the footwell to a Y near the filler door. Of the three lines on the Y, one comes from the footwell, one goes to the filler, the third goes to the trunk to unlock that.

The green line also goes from footwell to rear, but only connects to the trunk lock.

I'd test the filler element by itself with a Mity-Vac. If good, then reconnect the trunk and the filler red lines and plug the trunk green line near the trunk element. Apply the Mity-Vac to the third Y end on the filler Y and see if the trunk works. If so, then connect the red line from footwell to third Y end and disconnect in footwell and apply the Mity Vac there.

You are systemically testing each component.

Keep in the mind the locks need red suction to lock and green suction to unlock.